Broad beam light

ABSTRACT

A light projecting apparatus is disclosed. The apparatus has a head with first and second light sources. There is a first reflector and a second reflector respectively disposed proximate to the first and second light sources. Each of the first and second reflectors has a concave reflective surface and a convex reflective surface configured to form light emitted by the respective light source into an illumination pattern having a central region having a substantially uniform distribution of luminous intensity and a taper region having a tapered luminous intensity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S. patentapplication Ser. No. 17/281,204 filed Mar. 29, 2021, which claimspriority to international application PCT/US2020/036483 filed on Jun. 5,2020, which claims priority to U.S. provisional patent application62/858,292 filed on Jun. 6, 2019, all of which are incorporated hereinby reference in their entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION

A portion of the material in this patent document may be subject tocopyright protection under the copyright laws of the United States andof other countries. The owner of the copyright rights has no objectionto the facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the United States Patent andTrademark Office publicly available file or records, but otherwisereserves all copyright rights whatsoever. The copyright owner does nothereby waive any of its rights to have this patent document maintainedin secrecy, including without limitation its rights pursuant to 37C.F.R. § 1.14.

BACKGROUND 1. Technical Field

The technology of this disclosure pertains generally to an illuminationapparatus, and more particularly to a flashlight with a rectangular beampattern.

2. Background Discussion

Generally, existing flashlights generate a circular, focused beampattern that results in uneven dispersion in the form of a highintensity spot and much larger low-intensity spill pattern.

A significant need exists for the ability to illuminate one or morewalls of a room with a uniform beam pattern that fills one or more wallsurfaces. Existing systems fail to provide a uniform rectangular beampattern for achieving such illumination.

BRIEF SUMMARY

An aspect of the present description is a rectangular wide-beamflashlight that utilizes a plurality of LEDs positioned in uniquelyformed optical elements to generate a uniform, rectangular beam patternconfigured to substantially illuminate one or more walls in a room.

In one embodiment, the flashlight uses a sequential array of LEDs thatare radially disposed at or within optical elements or cavitiesconfigured to combine the output of the LEDs to form a substantiallyuniform and seamless, high-aspect ratio or wide rectangular beam foradequately illuminating one or more walls in a room.

In a further embodiment, the array of LEDs are disposed in a circulararray that forms a combined angular swath greater than 180 degrees, andthe beams from neighboring LEDs are configured to overlap so as not toprovide black spots within the illumination beam. The optical elementsmay also be configured to taper the luminous intensity of respectivebeams at lateral fringes of beam where overlap may occur to blend orfuse the beams at the overlap locations.

In another embodiment, the wide-beam flashlight comprises a pair ofretractable legs that may be extended from the flashlight housing toallow the flashlight to be propped up in a “hands-free” configuration.

The flashlight may also comprise logic components and a switch forselective control of each LED in the array of LEDs to provide varyingbeam widths or illumination patterns, and strobe option for dynamicillumination at a set frequency (e.g. flash mode).

Further aspects of the technology described herein will be brought outin the following portions of the specification, wherein the detaileddescription is for the purpose of fully disclosing embodiments of thetechnology without placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The technology described herein will be more fully understood byreference to the following drawings which are for illustrative purposesonly:

FIG. 1 is a perspective view of a rectangular wide-beam flashlight withlegs forming a bipod structure in an extended configuration inaccordance with the present disclosure.

FIG. 2 is a bottom view of the rectangular wide-beam flashlight of FIG.1 with legs in a collapsed or retracted configuration.

FIG. 3 is a side view of the rectangular wide-beam flashlight of FIG. 1with legs in a collapsed or retracted configuration.

FIG. 4 is a perspective view of the rectangular wide-beam flashlight ofFIG. 1 with top cover and lens removed and legs in a collapsed orretracted configuration,

FIG. 5 is a top view of the rectangular wide-beam flashlight of theconfiguration shown in FIG. 4.

FIG. 6 is an alternative optical element configuration incorporating aTotal Internal Reflection (TIR) lens configured to shape and/or dispersea rectangular beam.

FIG. 7 is an alternative optical element configuration incorporating areflector configured to shape and/or disperse a rectangular beam.

FIG. 8 shows a side view of two adjacent optical elements and resultingbeam patterns in accordance with the present description.

FIG. 9 shows the beams of the adjacent lenses of FIG. 8 projected on aplanar surface (e.g. wall).

FIG. 10 is an exploded view of an embodiment of an optical head withfive light shaping modules for a rectangular wide-beam flashlight inaccordance with the present disclosure.

FIG. 11 is an exploded front perspective view of a single light shapingmodule according to an embodiment of the present disclosure,

FIG. 12 is a front perspective assembled view of the optical head ofFIG. 10.

FIG. 13 is a top view of a horizontal full cross section of the opticalhead of FIG. 12 taken through lines 13-13.

FIG. 14 is a side full cross section view of the optical head of FIG. 12taken through lines 14-14.

FIG. 15 is a perspective full cross section view of the optical head ofFIG. 12 taken through lines 15-15.

FIG. 16 is a front center view of the optical head of FIG. 12.

FIG. 17 is a front center view of an individual light shaping moduleaccording to an embodiment of the present disclosure.

FIG. 18 is top view of a horizontal full cross section of the lightshaping module of FIG. 17 taken through lines 18-18.

FIG. 19 is a side view of a vertical full cross section of the lightshaping module of FIG. 17 taken through lines 19-19.

FIG. 20 is a ray pattern illustrating the narrow vertical pattern oflight emitted from the optical head of FIG. 12.

FIG. 21 is a ray pattern illustrating the wide horizontal pattern oflight emitted from the optical head of FIG. 12.

FIG. 22 is a diagram illustrating an embodiment of the relationshipbetween the homogenizer and the beam shaping optic in the light shapingmodule of the present disclosure.

FIG. 23 is a center front view of the individual light shaping module ofFIG. 17 rotated 90 degrees counterclockwise in relation to the view inFIG. 16.

FIG. 24 is a side view of a vertical full cross section of the lightshaping module of FIG. 23 taken through lines 24-24 of FIG. 23 withsample dimensions indicated.

FIG. 25 is a top view of the light shaping module of FIG. 23 with sampledimensions indicated.

FIG. 26 is a side view of a vertical full cross section of the lightshaping module of FIG. 25 taken through lines 26-26 with sampledimensions indicated.

DETAILED DESCRIPTION

FIG. 1 through FIG. 5 show various views of a rectangular wide-beamflashlight 10 in accordance with the present disclosure. Flashlight 10comprises a housing having a first end forming a battery compartment 20The battery compartment 20 comprises a cavity (not shown) that isconfigured to house a portable power source such as a battery orrechargeable batteries (not shown) and also acts as the handle forholding the flashlight. A tail cap 22 releasably attaches to the rearend of the battery compartment 20 e.g. so that it can be removed toallow access to the battery compartment to change the batteries. Anoptical head 12 is disposed at the second end of the housing oppositethe battery compartment 20 and houses optical components (see FIG. 4 andFIG. 5), switch 24, strobe button 26, charging/communication port 28(e.g. micro-USB or the like), toothed or serrated forward edges 16,cover/lens 14 and retractable legs 18.

FIG. 1 shows the legs 18 legs in an extended configuration. FIG. 2 andFIG. 3 show the legs 18 in a collapsed or retracted configuration viarotation of the legs toward the battery compartment 20. The legs 18 forma bipod structure (which may also be one continuous piece—not shown)that form two feet when the legs are deployed to use the flashlight 10hands-free to illuminate a specific area for a period of time. The legs18 attach to the lower, flat surface of the optical head 12 with viahinges 30 located on the bottom surface of the optical head. The legs 18are stored against the side or bottom of the flashlight (FIG. 2 and FIG.3) when they are not in use and open forwards and outwards when they aredeployed (FIG. 1). When deployed, the two feet of the legs 18 and pointcontact of the tail cap 22 at the end of the battery compartment 20 forma tripod structure that points the optical head slightly upward from thesurface upon which it is disposed. A stop (not shown) may beincorporated into the hinge 30 or the optical head 12 in order to knitthe travel of the legs 18 so they are stable when supporting theflashlight. The legs 18 are hinged such that they fold outward inopposite directions and when at full extension are positioned overcenter to prevent them from collapsing under the weight of theflashlight 10. When the legs 18 are in the closed position, they areheld in place by friction in the hinge 30 or by an interference snapfeature or detent (not shown) incorporated into the optical head 12 ofthe flashlight. The distal end of each leg is configured to rest on theground or other surface when the flashlight is used in “hands free”mode. In one embodiment, the hinge 30 comprises a clevis hinge.

The cover/lens 14 is configured to provide protection to the opticalcomponents and may comprise a clear arcuate cover that wraps around thefront end of the optical head 12. The cover/lens 14 may be sealedbetween the upper surface and the lower surface of the optical head 12with a rubber gasket (not shown). The cover/lens 14 is preferablydisposed in a convex shape to reduce the likelihood that the lens willbreak if the flashlight is inadvertently dropped on the ground andstrikes a rock. Cover/lens 14 may be shaped to provide certain opticalqualities. For example, the lens 14 may have an hourglass-shapedcross-section (FIG. 3) to provide vertical collimation, or otheroptical/dispersion characteristic to the emitted flashlight beam. Theforward edges 16 of the optical head 12 protrudes farther in front ofthe cover/lens and provides additional protection to the lens againstbreakage. The forward edges 16 are preferably serrated so that it can beused as a weapon in the event that the flashlight user is beingattacked.

The tail cap 22 is preferably attached to the battery compartment 20 viathreads on both pieces and is sealed to prevent water leakage into thebattery compartment with a rubber O-ring (not shown) that fits betweenthe tail cap and the battery compartment. The tail cap 22 is preferablylarger in diameter than the battery compartment 20, which helps toprevent the flashlight from slipping out of the user's hand, and alsohelps to form a contact surface to form a 3-point or tripod structurewith the extended legs 18.

The battery compartment 20, optical head 12 and tail cap 22 of theflashlight 10 are preferably made out of aluminum, but may also be madeout of plastic or steel. The optical head 12 may be made as a singlepart or made out of two shells that are fastened together with screws(not shown) connecting them. Rubber gaskets (not shown) may be used toseal all joints of the housing to prevent leakage of water.

FIG. 4 shows a perspective view of the rectangular wide-beam flashlight10 with top cover and lens 14 removed to illustrate the componentstherein. This embodiment of the rectangular wide-beam flashlight 10shows a configuration with five light sources 50 sequentially disposedin a radial array. In one embodiment, the light sources comprisehigh-power light emitting diodes (LEDs). While a 5-LED array is shownand described, it will be appreciated that the array may range from 2 to7 or more LEDs. Each LED 50 is disposed on a mounting bracket 34 at theend of a circuit board 32, which is coupled to the switch 24, strobebutton 26, charging/communication port 28 and associated logiccomponents 36. Each LED 50 is positioned inside or adjacent a dedicatedoptical element 40 that is configured to direct and/or shape lightemitted from the LEDs to generate the desired beam pattern. In theembodiment shown in FIG. 4 and FIG. 5, the optical elements 40 areconfigured as diverging reflectors shaped to form a rectangular patternwhen illuminating a planar surface. The distal ends of the opticalelements 40 are secured to a circular-shaped bracket 38 that has one ormore windows for allowing transmission of light. The optical elements 40may be made out of polished metal, glass, plastic, and may have areflective coating.

While LEDs 50 may comprise any type of light source, in one embodimentthey comprise high-power LEDs (e.g. 1000 lumen Cree LEDs). In oneembodiment, the optical elements 40 are sized to be approximately 1.3inches in length, with a width at the proximal end (at the LED 50) beingapproximately ⅓ the width at the distal end.

FIG. 5 is a top view of the rectangular wide-beam flashlight 10,illustrating the resulting beam pattern. Each LED 50 emits a dedicatedbeam 42, having an angular dispersion ϕ in the X-Y plane, as shaped bythe respective optical element 40. So as not to create dark spots, andto alleviate need for perfect alignment of LEDs 50 and/or opticalelements 40, the LEDs 50 and optical elements 40 are aligned/shaped sothat each of the beams 42 has a slight overlap 44 at an angle β. Theindividual beams 42 form a solid angular swath α in the X-Y plane of theflashlight 10.

In the embodiment shown in FIG. 1 through FIG. 5 for a 5-LED array, thesliding switch 24 has 4 positions programed within the logic components36 for variable illumination of the LED array. In the first position,the power to all of the LEDs is off. In the second position, only thepower to the front (center-most) LED is on. In the third position, thepower to the front LED is on along with the power to each LED adjacentto the front LED. In the fourth position all 5 LEDs are powered on. Itis appreciated that the switch 24 and/or logic components 36 maycomprise different functionality to provide a number of variousillumination patterns. For example, the lights may be selectivelyoperated (e.g. via switch 24 or additional switches/buttons not shown)to provide “side-only” illumination where one or more central beams areturned off while left and right side beams are on, essentiallystraddling a forward region deliberately kept dark with two spaced-apartillumination regions. Therefore, it will be appreciated various switchconfigurations and functions can be employed without limitation,including but not limited to off/on/dimmable thumb control functions andslide and/or rotary configurations.

The strobe button 26 is located forward of the sliding switch 24 and maybe programmed to activate all of the LEDs simultaneously with the rightfacing and left facing LEDs in strobe “flash bang” mode.

The USB connector 28 is located forward of the strobe button 26. Theprimary function of the USB connector 28 is to provide chargingcapability for the batteries. In addition, the USB connector 28 mayprovide digital signal connectivity between the circuit board 32contained inside the housing and an external device (not shown) such asa cell phone or laptop computer. Digital connectivity may be used tomonitor power consumption of the batteries, or to program a digitalcontroller (e.g. within logic components 36) located on the circuitboard 32 for custom functionality of the buttons and LEDs. The USBconnector 28 may also be used to provide power from the flashlightbatteries to an external device such as a cell phone.

In one embodiment, each LED 50, when illuminated, generates a resultingbeam of light that has a nearly rectangular projected shape with anangular width ϕ (in the X-Y plane) of approximately 45-50 degrees and aheight (e.g. angular projection in the Z-Y plane or Z-X plane) ofapproximately 23 degrees. In this configuration, when all five LEDs 50are simultaneously illuminated, the resulting combined illumination ofthe beams is a rectangular projected angular swaths of light that isapproximately 225 degrees in width and 23 degrees in height. It isappreciated that the number of LEDs 50, and or shape, sizing ororientation of the optical elements 40 may be configured to cover anynumber of different configurations or ranges (e.g. projected angularswath α ranging from 120 degrees to 270 degrees or more, and morepreferably between 180 degrees and 225 degrees).

The overlap angle β may be correspondingly small (e.g. 2 degrees to 5degrees, or even one degree or less in some configurations), andconfigured to coincide at a specified distance from the flashlightcorresponding to a particular expected range of distances (e.g. 10feet-30 feet).

It is appreciated that the optical element shape/sizing and resultingbeam patterns and illumination displayed in FIG. 5 through FIG. 9 arefor illustrative purposes only, and may not be to scale or represent anexact angle or curvature. For example, such representations may beexaggerated so as to show up on illustration where they may nototherwise be perceptible.

FIG. 6 shows an alternative embodiment of an optical element 40 a thatcomprises a Total Internal Reflection (TIR) lens configured to shapeand/or disperse a rectangular beam 42 a and specifically modified toprovide substantially uniform light distribution across angularprojection 4, and having an intensity that tapers at a portion of thelateral edges of the beam. 42 a. In this configuration, all light isinternally modified (e.g. reflected, refracted, or dispersed) via one ormore of internal surfaces 48 and external surfaces 41. Internal surfaces48 and external surfaces 41 are preferably shaped to provide a mostlyuniform distribution across the majority of angular projection ϕ.However, one or more surfaces, (e,g. internal surface 52 or externalsurface 46) is shaped or otherwise modified (e.g. roughened, coated,painted, etc.) so as to reflect, refract or disperse light to taper theintensity at or near the overlap region 44 of two adjacent beams 42 (seetaper region having angle 4′, as shown in FIG. 8). The taper regionangle ϕ may vary depending on the desired taper profile, but maytypically be in the range of 2 to 5 degrees.

FIG. 7 shows an alternative embodiment of an optical element 40 c thatcomprises a reflector configured to shape and/or disperse lightuniformly across a beam 42 c configured to generate a rectangularpattern of light when illuminating a planar surface. As seen in FIG. 7,light from LED 50 is emitted outward from a diverging cavity formed bythe inner surface 54 of the reflector 40 c, and may be in the form ofdirect light 45, or light 43 that is reflected off the interiorreflective surface 54 of reflector 42 c. The two side walls ofreflective surface 54 are shaped so as to generate uniform lightdistribution across a substantial portion of the angular projection ϕ ofbeam 42 c (FIG. 7 shows the light distribution in the X-Y plane fromleft and right side-walls making up surface 54.

A similar structure of the internal surface 54 may be generatedvertically for upper and lower side walls (not shown) so as to generatea uniform distribution in the X-Z plane). Lens 40 a of FIG. 6 maysimilarly have a 4-wall structure for surfaces 44 and 48 of the lens. Inone embodiment, the inner wall surfaces 54 comprise a squaretrumpet-like shape that comprise a compound curvature including a firstconcave inner surface 56 that focuses reflected light inward, and aconvex outer surface 58 that distributes light outward toward thelateral edges of beam 42 c. With respect to the cross-section of thearray of LEDs when viewing the inner surface 54, the concave segment 56at the center that transitions into the convex segment 58 toward theperiphery of the reflector cavity 40 c, which may seamlessly lead intothe convex surface of the adjacent reflector cavity to form a somewhatsinusoidal surface about a half-radius.

It is appreciated that a portion of the curvature or surface 58 may beshaped, coated, etc. to provide an intensity taper region having angleϕ′, as shown in FIG. 8.

FIG. 8 shows a side view of two adjacent lenses 40 a and 40 bcommensurate with the lens embodiment shown in FIG. 6, along withresulting respective beam patterns 42 a and 42 b projected on a planarsurface or wall 70. The lens 40 a shown on the left in FIG. 8 isconfigured to comprise a taper of the emitted luminous intensity atangle ϕ′ from both peripheral edges of the beam 42 a. Thus, this wouldserve to minimize overlap 44 “hot spots” by blending the output luminousintensity where two adjacent beams of light overlap and otherwise createa double brightness vertical band. Since the human eye generallyrequires 8 times the amount of light to perceive a brightness variationthat appears to be double in brightness, any increase in luminousintensity due to the gradual overlap may be barely, if at all,discernible to the user.

Correspondingly, the outer-most optical element 40 in the array (seeleft-most and right-most optical elements 40 in FIG. 5) may only have ataper region ϕ′ on the inside edge of the beam 42 b, as shown with lens40 b in FIG. 8 (in such case the reflector 40 b is the right-mostoptical element in the array). This would have the effect of providing asharp luminous intensity or bright line at the left and right edges ofthe combined beam pattern (e.g. at the furthest extent of the angularswath α, (see FIG. 5, see also FIG. 3 showing left-most optical element40 b disposed in the Y-axis)). While FIG. 5 shows all beams 42 from thearray being identical, it is appreciated that some of the LED 50 oroptical elements 40 may be distinct from another to achieve a slightlydifferent beam configuration (e.g. beam swath ϕ, taper, eta). To save onproduction costs, the array of optical elements 40 may also be madeidentical to each other.

FIG. 9 shows the beams 42 a and 42 b of the adjacent lenses of FIG. 8projected on a planar surface (e.g. wall 70) coincident with a graph ofthe luminous intensity I_(v) at given angles within the X-Y plane. Bothbeams 42 a and 42 b have constant luminous intensity regions 60 and 62I_(v) through most of the beam swath ϕ. Beam 42 a has tapers 64 and 68at both ends of a central region 62 having substantially uniformintensity, and beam 42 b has a taper 66 at one end (adjacent beam 42 a)of the substantially uniform intensity region 60 and no taper at the farend. The taper profiles shown in FIG. 9 are shown as linear curves thatdecrease from 100% intensity to 0% intensity within the taper region ϕ′,However, many different taper profile configurations are contemplated,including variation in slope, curvature (e.g. parabolic) and grade (e.g.50% taper at end of beam), tapers that are stepped, etc. It is furtherunderstood that the intensity values of the graph in FIG. 9 arerepresentative for illustration purposes, and actual luminous output mayhave variations from that shown that may or may not be perceptible tothe human eye.

It is appreciated that reflector 40 c shown in FIG. 7 may be modified toprovide the beam patterns 42 c to have similarly tapered edges as shownin FIG. 8. Optical elements 40 may also comprise a combination ofreflective, refractive, or dispersive optical elements to achieve thedesired illumination pattern.

It is further appreciated that the overlap defined by angle β in FIG. 8and FIG. 9 is preferably only configured to occur in the X-Y angularprojection where beams are configured to overlap, as no tapering in theangular projection in the Z-Y plane or Z-X plane may be needed ordesirable.

FIG. 10 through FIG. 16 illustrate an embodiment of an optical head 100for a rectangular wide-beam flashlight in accordance with the presentdisclosure as an alternative to the optical head 12 previouslydescribed. In this embodiment, the optical elements comprise a pluralityof light shaping modules 102 arranged side-by-side in an arcuate array.The light shaping modules are positioned between, and connected to, anupper retaining plate 104 a and a lower retaining plate 104 b. Theretaining plates and light shaping modules may be connected togetherusing any conventional means suitable for the materials used, such as,for example, holes and corresponding threads or other means with whichscrews, pins or other fasteners may used to securely connect the parts.

While smooth forward edges are shown on the retaining plates in thisembodiment, toothed or serrated forward edges can be included aspreviously described. The figures and related description are primarilydirected to the beam shaping and light emission characteristics of thisembodiment.

Each light shaping module is associated with a corresponding lightsource 106 such as a Cree LED as previously described. Each lightshaping module includes a rear opening 108 through which the lightsource can extend or through which the light source otherwise canproject light. In this regard, each light source is preferably solderedor otherwise attached to a circuit board 110 which in turn is attachedto the rear of the light shaping module. The circuit board can beattached to the light shaping module using any conventional meanssuitable for the materials used. For example, attachment may be madeusing screws, pins or other fasteners 112 that extend through thecircuit board and into corresponding holes 114 in the light shapingmodule. Due to the heat generated by Cree LEDs, the circuit boardpreferably has a metalized surface 116 on the LED side to act as a heatsink. The light sources are preferably soldered to traces 118 on thecircuit board, and plated through holes and traces or other connectors(not shown) can be provided for electrical connections to the lightsource.

A backing plate 120 with a coupling 122 is attached to the rear of theoptical head. The coupling 122 is configured for connection to a supportstructure such as a handle of the type previously described. The backingplate includes upper and lower flanges 124 a, 124 b for attachment tothe upper and lower retaining plates, respectively, using anyconventional means suitable for the materials used, such as, forexample, holes and corresponding threads or other means with whichscrews, pins or other fasteners may used to securely connect the parts.It will be noted that the backing plate also functions as a barrier toblock rearward protection of light so that the emitted light has anapproximate one-hundred and eighty degree field of projection.

Note that five light shaping modules are shown in the array as anon-limiting embodiment. Additional light shaping modules could be usedwhen desired, such as when increasing the size of the array for use as alight bar on a vehicle. If fewer light shaping modules are used, thebeam pattern would degraded even in a smaller array such as would beused in a handheld flashlight of the type described herein. Furthermore,multiple such arrays could be stacked.

In the embodiment shown, the array of light shaping modules isconfigured to shape and project light uniformly from the light sourcesinto a pattern with relatively constant angular divergence in both thehorizontal and vertical directions. The illumination pattern in thevertical direction is narrower than the pattern in the horizontaldirection and this illumination pattern appears substantiallyrectangular in shape when projected onto a surface that is equidistant(spherical) from the light source.

The configuration of a light shaping module in this embodiment isillustrated in more detail in FIG. 17 through FIG. 19. As illustrated,each light shaping module in this embodiment has two distinct sections:a homogenizer section (H) and a beam shaping optic section (BSO). Thehomogenizer section comprises a homogenizer 126. The beam shaping opticsection comprises reflective surfaces 128 that are shaped to provide thedesired beam forming and shaping characteristics. Each of these sectionshas different optical characteristics as will now be described.

The homogenizer collects light from the light source and generates arelatively uniform output surface that is rectangular in nature in orderto condition the beam to be projected. In this embodiment thehomogenizer has is a light pipe with a square input surface (face) 130and a square output surface (face) 132. The non-uniform light collectedby the light pipe at one end is transported to the other end of thelight pipe by mirrored reflections in such a way as to homogenize thelight. The length of the light pipe should be selected to achieve enoughlight bounces to homogenize the light intensity at the output end of thelight pipe.

It will be appreciated that light pipes can be flat mirrored surfaceswith input and output faces that are circular or of any polygon shapebut are typically rectangular, square, hexagonal in shape. The sizes ofthe input and output faces can be different for the same light pipe,which will change the angular projection output of the light pattern.The light pipe can be straight or tapered.

The beam shaping optic receives light from the homogenizer and radiatesthe light in a substantially uniform rectangular projected pattern. Inthis embodiment, the beam shaping optic comprises a Concentric ParabolicConcentrator (CPC) that conditions and shapes the beam to be projected.The inner surfaces 134 of the beam shaping optic are mirrored so thatthe light that is projected outward comprises a combination of directlight and light that is reflected off the mirrored surface. Light isprojected with a substantially uniform output over a controlled solidangle in the vertical and horizontal directions. The beam shaping opticcan comprise various materials such as, for example, a metal materialwith a highly polished surface or a plastic material with a reflectivecoating common in the industry.

As illustrated in FIG. 20 and FIG. 21, light rays 136 emitted from alight source are collected, homogenized and projected outward from theoptics produced by the inner reflective surface of the beam formingoptic, and comprises both direct light and light that is reflected offthe reflective surface of the beam forming optic. The reflectivesurfaces are configured to collect the light and generate a relativelyuniform projected light output over a controlled solid angle in the X-Zand Y-Z planes. FIG. 20 and FIG. 21 illustrate the narrow verticalpattern 138 of light rays (side view) and the wide horizontal pattern140 of light rays (top view), respectively.

FIG. 22 graphically illustrates the relationship between the homogenizerand the beam shaping optic. The homogenizer collects the light from thelight source at one end (left side) and transfers it to a location atthe other end (right side) where a relatively uniform illuminationprofile has been created. The beam shaping optic comprises reflectivesurfaces that project light entering at the small end (left side) of theoptic to the large end (right side) of the optic. Ray angles aretransformed to be projected from a large solid angle (wide angle withrespect to the z-axis) to a smaller solid angle (narrow angle withrespect to the z-axis) as it is reflected from the surfaces.

As described above, the basic shape of these types are optics are knownas a Concentric Parabolic Concentrator (CPC), CPCs are described indetail in W. T. Welford and R, Winston, “High Collection NonimagingOptics”, Academic Press (1989), for example, and thus will briefly bediscussed here.

For a hollow reflective optic where the internal surface is air, themaximum length of the CPC is given by:

$L = \frac{a\left( {1 + {\sin\;\theta}} \right)}{\tan\;{\theta sin}\;\theta}$

where a=the entrance aperture and θ=maximum projection angle in the x ory directions.

The length can be truncated, but it will reduce the sharpness edge ofthe light beam. Shortening the CPC length can be used to increase thetransition zone between the light and dark illuminated areas where beamsoverlap over lap from adjacent light patches.

The x or y coordinate (r) of points on the

as a function of the z coordinate along the axis is given by thepositive real root of this quadratic equation:

C²r² + 2(CSz + aP²)r + (z²S² − 2aCQz − a²PT) = 0 whereC = cos  θ, S = sin  θ, P = 1 + S, Q = 1 + P, and T = 1 + Q.

EXAMPLE 1

For an overall illumination pattern of 17 degrees by 180 degrees with 5reflectors with a 5 degree overlap, an angle of +/−21 degrees is neededin the y-direction. For a=1.85 mm and θ=21 degrees, L=18.26765,C=0.93358, S=0.35837, P=1.35837, Q=2.35837, and T=3.35837. Solving forthe positive real root to the quadratic equation for the x-directiongives the values in Table 1. The surface is truncated (z is less thanthe maximum length (L)) in order to control the overlap regions betweenadjacent reflector assembles so that a relatively uniform continuousbeam is achieved. In the x-direction, the 17 degree projection anglegives θ=8.5 degrees, L=96.12594, C=0.989016, S=0.147809, P=1.147809,Q=2.147809, and T=3.14780. Solving for the positive real root to thequadratic equation for the y-direction gives the values in Table 2. Thesurfaces can be truncated in order to achieve the best compromise ofcollection efficiency and size.

EXAMPLE 2

By way of example, and not of limitation FIG. 23 through FIG. 26illustrate dimensional relationships in a light shaping module toachieve a rectangular wide beam according to the presented technology.Unless otherwise specified: (1) all dimensions and SAG table values arein millimeters; (2) all reflective surfaces are symmetrical around the Yand Z dimensions center lines; and (3) all reflective surfaces have lessthan about 7 microns deviation.

In FIG. 24 and FIG. 26, the homogenizer reflective surface 200 isoptically reflective at about 60 angstroms rms, and X=0.020833(Z)+1.725where 0≤Z≤6. Table 3 and Table 4 are SAG tables showing the reflectivesurface contours 300, 400, respectively, for the beam shaping optic.

Surface 300 is optically reflective at about 60 angstroms rms and SAGTable 3 applies. The values in SAG Table 3 were determined according to:

For  0 ≤ Z 1 ≤ 30 $Y = \frac{{- b} + \sqrt{b^{2} - {4a\; c}}}{2a}$wherea=0.978152378b=0.292371705 (Z1)+4.874625844c=0.021847622 (Z1)²−7.859605043 (Z1)−12.36578432

Surface 400 is optically reflective at about 60 angstroms rms and SAGTable 4 applies. The values in SAG Table 4 were determined according to:

For  0 ≤ Z 2 ≤ 14 $Y = \frac{{- b} + \sqrt{b^{2} - {4a\; c}}}{2a}$wherea=0.871572413b=0.669130606 (Z2)+6.8271049c=0.128427587 (Z2)²−8.146386778 (Z2)−15.61310065

From the description herein, it will be appreciated that the presentdisclosure encompasses multiple embodiments which include, but are notlimited to, the following:

1. A light projecting apparatus, comprising: (a) a housing configured toretain one or more power sources; and (b) an optical head extending fromthe housing, the optical head comprising: (i) a plurality of opticalelements arranged in a sequential array; (ii) a plurality of lightsources configured to be powered from the one or more power sources,each said light source disposed adjacent or within a corresponding oneof said optical elements; (iii) each said optical element shaped tomodify a beam of light emitted from a corresponding light source togenerate a rectangular illumination pattern when projected on a planarsurface; and (iv) wherein emitted light beams from adjacent opticalelements overlap along at least one side of the emitted light beams suchthat adjacent light beams form a contiguous beam having a higher aspectratio than each of the emitted light beams in isolation.

2. The apparatus of any preceding or following embodiment, wherein theoptical elements are shaped to taper luminous intensity of each emittedlight beam at a specified location corresponding to the adjacent beamoverlap.

3. The apparatus of any preceding or following embodiment, wherein thelight sources and optical elements are shaped to form a contiguousrectangular beam having an angular swath greater than 180 degrees.

4. The apparatus of any preceding or following embodiment, wherein eachoptical element comprises one or more surfaces that reflect, refract ordiffuse light to taper the luminous intensity at a specified angle fromperipheral lateral edges of the emitted beam of light to form an angulartaper region at the lateral edges.

5. The apparatus of any preceding or following embodiment, wherein theone or more surfaces of the optical elements generate a central regionbetween angular taper regions at the lateral edges, the central regioncomprising a substantially uniform distribution of luminous intensity.

6. The apparatus of any preceding or following embodiment, wherein atleast one of the optical elements comprises a reflector having a concavesegment and convex segment to distribute light substantially uniformlyacross the central region.

7. The apparatus of any preceding or following embodiment, wherein atleast one of the optical elements comprises a lens shaped to directlight from a respective light source to form a total internal reflection(TIR) beam of collimated light at least across the central region.

8. The apparatus of any preceding or following embodiment, wherein thelight sources comprise light emitting diodes (LEDs)

9. The apparatus of any preceding or following embodiment, wherein thelight sources and optical elements are disposed in a radial array.

10. The apparatus of any preceding or following embodiment, furthercomprising a curved lens disposed opposite the LEDs from the opticalelements to cover the light sources and optical elements.

11. The apparatus of any preceding or following embodiment, wherein thelens has a curvature configured to provide further dispersion of light.

12. The apparatus of any preceding or following embodiment: wherein thehousing comprises an elongate first end for housing the one or morebattery power sources and providing a handhold for a user, and saidoptical head at a second end for housing the light sources and opticalelements; wherein the housing at the optical head comprises a surfacefor retaining a retractable bipod structure having a first foldedposition disposed flush with or retained in the housing and a secondextended position that forms a pair of feet; and wherein upon placingthe flashlight on a working surface with the bipod structure in theextended position, the pair of feet and first end of the housing form atripod structure for securing the flashlight in a hands-free positionand orienting the optical head upward at a specified angle with respectto the working surface.

13. The apparatus of any preceding or following embodiment, wherein thebipod structure comprises a hinge at one end and extends downward andoutward in a lateral direction with respect to the optical head in theextended position.

14. The apparatus of any preceding or following embodiment, wherein thearray comprises at least three light sources comprising a center lightsource and two peripheral light sources.

15. The apparatus of any preceding or following embodiment, wherein thelight sources are coupled to a switch disposed within the housing, theswitch having a first position where all light sources are off, a secondposition where only the center light source is on, and a third positionwhere the center and periphery light sources are on.

16. The apparatus of any preceding or following embodiment:

wherein the array comprises at least five light sources comprising twoouter peripheral light sources opposite the center light source from theperipheral light sources; and wherein the switch has a fourth positionthat illuminates the entire array of five light sources.

17. The apparatus of any preceding or following embodiment, furthercomprising a second switch that activates all of the light sources tostrobe or flash one or more of the light sources.

18. A light projecting apparatus, comprising: (a) a housing configuredto retain one or more power sources; and (b) an optical head extendingfrom the housing, the optical head comprising: (i) a plurality ofoptical elements arranged in a sequential array; (ii) a plurality oflight sources configured to be powered from the one or more powersources, each said light source disposed adjacent or within acorresponding one of said optical elements; (iii) each said opticalelement shaped to modify a beam of light emitted from a correspondinglight source to generate a rectangular illumination pattern whenprojected on a planar surface; and (iv) wherein emitted light beams fromadjacent optical elements overlap along at least one side of the emittedlight beams such that adjacent light beams form a contiguous beam havinga higher aspect ratio than each of the emitted light beams in isolation;(c) wherein the housing comprises an elongate first end for housing theone or more battery power sources and providing a handhold for a user,and an optical head for housing the light source; (d) wherein thehousing at the optical head comprises a surface for retaining aretractable biped structure having a first folded position disposedflush with or retained in the housing and a second extended positionthat forms a pair of feet; and (e) wherein upon placing the flashlighton a working surface with the biped structure in the extended position,the pair of feet and first end of the housing form a tripod structurefor securing the flashlight in a hands-free position and orienting theoptical head upward at a specified angle with respect to the workingsurface.

19. A light projecting apparatus, comprising: (a) a housing configuredto retain one or more power sources; and (b) an optical head extendingfrom the housing, the optical head comprising: (i) a plurality ofoptical elements arranged in a sequential array; (ii) a plurality oflight sources configured to be powered from the one or more powersources, each said light source disposed adjacent or within acorresponding one of said optical elements; (iii) each said opticalelement shaped to modify a beam of light emitted from a correspondinglight source to generate a rectangular illumination pattern whenprojected on a planar surface; (iv) wherein emitted light beams fromadjacent optical elements overlap along at least one side of the emittedlight beams such that adjacent light beams form a contiguous beam havinga higher aspect ratio than each of the emitted light beams in isolation;(v) wherein the optical elements are shaped to taper luminous intensityof each emitted light beam at a specified location corresponding to theadjacent beam overlap; (vi) wherein optical elements comprise one ormore surfaces that reflect, refract or diffuse light to taper theluminous intensity at a specified angle from peripheral lateral edges ofthe emitted beam of light to form an angular taper region at the lateraledges; and (vii) wherein the one or more surfaces of the opticalelements generate a central region between angular taper regions at thelateral edges, the central region comprising a substantially uniformdistribution of luminous intensity.

20. The apparatus of any preceding or following embodiment: wherein thelight sources and optical elements are disposed in a radial array; andwherein the light sources and optical elements are shaped to form acontiguous rectangular beam having an angular swath greater than 180degrees.

21. The apparatus of any preceding or following embodiment, wherein thelight sources and optical elements are shaped to form a contiguousrectangular beam having an angular swath greater than 220 degrees.

22. A optical head apparatus for a flashlight, comprising: (a) aplurality of optical elements arranged in a sequential array; (b) aplurality of light sources configured to be powered from one or morepower sources, each said light source disposed adjacent or within acorresponding one of said optical elements; (c) each said opticalelement shaped to modify a beam of light emitted from a correspondinglight source to generate a substantially rectangular illuminationpattern when projected on a planar surface; (d) wherein emitted lightbeams from adjacent optical elements overlap along at least one side ofthe emitted light beams such that adjacent light beams form a contiguousbeam having a higher aspect ratio than each of the emitted light beamsin isolation.

23. A optical head apparatus for a flashlight, comprising: (a) aplurality of optical elements arranged in a sequential array; (b) aplurality of light sources, each said light source associated with acorresponding one of said optical elements; (c) each said opticalelement shaped to modify a beam of light emitted from a correspondinglight source to generate a substantially rectangular illuminationpattern when projected on a planar surface; (d) wherein emitted lightbeams from adjacent optical elements overlap to collectively generate acontiguous beam that forms a substantially rectangular illuminationpattern which projected on a planar surface, wherein said contiguousbeam has a higher aspect ratio than each of the emitted light beams inisolation.

24. The apparatus of any preceding or following embodiment, wherein eachsaid optical element comprises a homogenizer section and a beam shapingoptic section.

25. The apparatus of any preceding or following embodiment, wherein thehomogenizer collects and conditions light from the light source.

26. The apparatus of any preceding or following embodiment, wherein thebeam shaping optic section comprises reflective surfaces that receivelight from the homogenizer section and radiate the light in asubstantially uniform rectangular projected pattern.

As used herein, the singular terms “a,” “an,” and “the” may includeplural referents unless the context clearly dictates otherwise.Reference to an object in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”

As used herein, the term “set” refers to a collection of one or moreobjects. Thus, for example, a set of objects can include a single objector multiple objects.

As used herein, the terms “substantially” and “about” are used todescribe and account for small variations. When used in conjunction withan event or circumstance, the terms can refer to instances in which theevent or circumstance occurs precisely as well as instances in which theevent or circumstance occurs to a close approximation. When used inconjunction with a numerical value, the terms can refer to a range ofvariation of less than or equal to ±10% of that numerical value, such asless than or equal to ±5%, less than or equal to ±4%, less than or equalto ±3%, less than or equal to ±2%, less than or equal to ±1%, less thanor equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to±0.05%. For example, “substantially” aligned can refer to a range ofangular variation of less than or equal to ±10°, such as less than orequal to ±5°, less than or equal to ±4°, less than or equal to ±3°, lessthan or equal to ±2°, less than or equal to ±1°, less than or equal to±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°.

Additionally, amounts, ratios, and other numerical values may sometimesbe presented herein in a range format. It is to be understood that suchrange format is used for convenience and brevity and should beunderstood flexibly to include numerical values explicitly specified aslimits of a range, but also to include all individual numerical valuesor sub-ranges encompassed within that range as if each numerical valueand sub-range is explicitly specified. For example, a ratio in the rangeof about 1 to about 200 should be understood to include the explicitlyrecited limits of about 1 and about 200, but also to include individualratios such as about 2, about 3, and about 4, and sub-ranges such asabout 10 to about 50, about 20 to about 100, and so forth.

Although the description herein contains many details, these should notbe construed as limiting the scope of the disclosure but as merelyproviding illustrations of some of the presently preferred embodiments.Therefore, it will be appreciated that the scope of the disclosure fullyencompasses other embodiments which may become obvious to those skilledin the art.

All structural and functional equivalents to the elements of thedisclosed embodiments that are known to those of ordinary skill in theart are expressly incorporated herein by reference and are intended tobe encompassed by the present claims. Furthermore, no element,component, or method step in the present disclosure is intended to bededicated to the public regardless of whether the element, component, ormethod step is explicitly recited in the claims. No claim dement hereinis to be construed as a “means plus function” dement unless the elementis expressly recited using the phrase “means for”. No claim elementherein is to be construed as a “step plus function” element unless thedement is expressly recited using the phrase “step for”.

TABLE 1 z y 0 1.8500 1 2.4529 2 2.9289 3 3.3172 4 3.6402 5 3.9120 64.1424 7 4.3385 8 4.5052 9 4.6468 10 4.7664 11 4.8664 12 4.9491 135.0162 14 5.0691 15 5.1092 16 5.1374 17 5.1547 18 5.1620 18.26765 5.1599

TABLE 2 z x 0 1.8500 1 2.6153 2 3.2435 3 3.7823 4 4.2569 5 4.6825 65.0691 7 5.4237 8 5.7514 9 6.0561 10 6.3409 11 6.6081 12 6.8598 137.0975 14 7.3227 15 7.5364 16 7.7396 17 7.9333 18 8.1181 19 8.2947 208.4637 21 8.6256 22 8.7809 23 8.9299 24 9.0730 25 9.2105 26 9.3429 279.4702 28 9.5929 29 9.7111 30 9.8250

TABLE 3 SAG Table A Z1 Y 0 1.8500 1 2.6153 2 3.2435 3 3.7823 4 4.2569 54.6825 6 5.0691 7 5.4237 8 5.7514 9 6.0561 10 6.3409 11 6.6081 12 6.859813 7.0975 14 7.3227 15 7.5364 16 7.7396 17 7.9333 18 8.1181 19 8.2947 208.4637 21 8.6256 22 8.7809 23 8.9299 24 9.0730 25 9.2105 26 9.3429 279.4702 28 9.5929 29 9.7111 30 9.8250

TABLE 4 SAG Table B Z2 Y 0 1.8500 1 2.4529 2 2.9289 3 3.3172 4 3.6402 53.9120 6 4.1424 7 4.3385 8 4.5052 9 4.6468 10 4.7664 11 4.8664 12 4.949113 5.0162 14 5.0691

The invention claimed is:
 1. A light projecting apparatus, comprising: ahead; a first light source and a second light source, both coupled tothe head; a first reflector and a second reflector respectively disposedproximate to the first and second light sources, each of the first andsecond reflectors comprising a concave reflective surface and a convexreflective surface configured to form light emitted by the respectivelight source into an illumination pattern comprising a central regionhaving a substantially uniform distribution of luminous intensity and ataper region having a tapered luminous intensity.
 2. The apparatus ofclaim 1, wherein the taper region formed by the first reflector overlapsthe taper region formed by the second reflector so as to form a singlecontiguous rectangular illumination pattern having a substantiallyuniform distribution of luminous intensity.
 3. The apparatus of claim 2,wherein the single contiguous rectangular illumination pattern has aheight and a width that is at least four times the height.
 4. Theapparatus of claim 3, wherein the width is at least six times theheight.
 5. The apparatus of claim 2, wherein the single contiguousrectangular illumination pattern has an angular swath of at least 120degrees.
 6. The apparatus of claim 5, wherein the angular swath is atleast 180 degrees.
 7. The apparatus of claim 2, wherein the singlecontiguous rectangular illumination pattern has a height of less than 23degrees.